Single-crystal-to-single-crystal Transformation of the Dichloromethane Solvate of the Shiff Base Manganese(III) Complex to a Solvent Free Material

The chloride complex of Mn(III)with an optically active Schiff base derived from3,5-tert-butyl-salicyl aldehyde and(1R,3S)-1,2,2,-trimethylcyclopentane-1,3-diaminecrystallizes as a 1 : 1 solvate (I) withCH₂Cl₂ and transforms at room temperature toa solvent-free compound (II) without destructionof the crystals. Two X-ray diffraction experimentscarried out on the same crystal at 120 K revealed thatthe guest CH₂Cl₂ molecules are completelyenclosed in the host matrix and that drasticconformational changes of the complex molecules occurduring removal of solvent. A possible mechanism of thecrystal transformation is disscused. The spectralevidence on association of the metal complex withdichloromethane in solution are demonstrated.